Process of making indoxyl, &amp;c.



Ta ia/ll whom/it ma concern.- Be it known that I, AUGUSTUS BIsonLER, doctor of philosophy and chemist, a subject STATES PATENT OFFICllG g AUGUSTUS BISGHLER, OFBASEL,SW1TZERLAND, ASSIGNORTO ,THE FIRM OFBASLE CHEMICAL WORKS, or ,BASEL, SWITZERLAND.

PRQGESS F MAKI G UINDOXYL, ac.

Specification of Letters Patent.

Patented Dec. 25, 1906.

Application filed. September 1, 1904. Serial No. 223,013-

of the Emperor of Russia, and a resident of Basel, Switzerland, have invented new and useful Improvements in the Manufacture of Indoxyl, Its Homologues, and Their Derivaalkalies, according to the method of Heu a er if sodium amid or sodium oxid is added to the mixture of phenylglycin salt and tives, of which the following is a clear and complete specification.

Byfmelting the phenylglycin salts with mann, only little indoxyl, and therefore ind'io, is obtained. The formation of indoxyl t es placejin a considerably smoother manalkali. Anaddition of alkali metals, such as fsodium to the, melt will also improve the =-yie1d of disadvantage about the latter proceeding.

indoxyL. There is, however, a great If only small proportions of sodiumare added to the melt of phenylglycin and alkali, the

i yield of indoxyl is practically little better than that obtained according to the process of Heumann. By operatingwith lar er pro- A portions of sodium more indoxyl is formed,

but the sodium in that case acts toward dee, ofindoxy composition, so that finally an impure indigo i is obtained, containing, for instance, only seventy per cent. of indigo.

By the 1present invention a very good yield and therefore of indigo, is obtained by reactmgwith alcohol in the'form ofvapor I on the mixture of alkali, sodium, and phenylglycin or its salts heated up to the formation of indoxyl, The presence of alcohol. pre-.

vents decomposition and considerably increases the yield of indoxyl.

To illustrate the invention, the following example may be given: Fifteen parts of sodium and forty parts ofthepotassium salt of i *phenylglycin are added, while stirring well,

to one hundred and forty parts of anhydrous caustic alkali (as potasslum hydroxid, for

I Thereupon tenparts' of absolute alco 01 in example) heated to about 250 centi rade.

the form of vapor are introduced by means of e formation of indoxyl does not increase any longer. The mass is discorresponding indigo-leuco derivatives may be obtained in very good yields, according to the above process.

In the described process the alcohol will react with the sodium and the caustic potash, (potassium hydroxid,) producing amixture of sodium and potassium alcoholates, which mixture will at once in the state of formation act in a condensating manner on the arylglycin salt, at the same time regenerating the alcohol. This intermediately-formed variable mixture of alcoholates is different from the particular mixture of alcoholates of always the same constant composition which is formed according to my United States Patent No. 7 61,440, where in a solution of caustic potash and alcohol an equivalent quantity of sodium is dissolved, the excess of alcoholbeing subsequently distilled off in warm.

The above rocedure also difiers fromthat described 1n United States Patent No.

737,836,.according' to which the phenylglycin salt is condensed in the presence of a caustic alkali with sodium or potassium alcoholate, for the reason that by the process of said United States Patent No. 737,836 no variable mixtures of alcoholates can be formed, but only a uniform alcoholate. .What I claim is 1. The herein-described rocess for the manufacture of indoxyl, its omolo ues and their derivatives by reacting with a cohol in the form of vapor on mixtures'of alkali, sodium and alkali salts of the arylglycins andof the formation of indoxyl, and by continuing afterward to heat until theformation of the.

their derivatives, previously heated up to r manufacture of indoxyl, its omolo ues and their derivatives by reacting with a cohol in the form of vapor on mixtures of potassium my name, this 20th day of August, 1904, in the presence of two subscribing Witnesses.

AUGUSTUS BISOHLER.

hydroxid, sodium and alkali salts of the arylgly'cins and of their derivatives, previously heated up to the formation of indoxyl, and by continuing afterward, to heat until 5 the formation of the indigo-leuco products is completed.

Witnesses: I

GEO. GIFFORD,

In Witness whereof I have hereunto signed AMAND RI'rrER. 

